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Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

2009

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Nanoparticles

University of Massachusetts Boston

Articles 1 - 4 of 4

Full-Text Articles in Physical Sciences and Mathematics

Impact Of High-Order Surface Plasmon Modes Of Metal Nanoparticles On Enhancement Of Optical Emission, Greg Sun, Jacob B. Khurgin, C. C. Yang Oct 2009

Impact Of High-Order Surface Plasmon Modes Of Metal Nanoparticles On Enhancement Of Optical Emission, Greg Sun, Jacob B. Khurgin, C. C. Yang

Physics Faculty Publications

We consider the impact of high-order surface plasmon modes supported by the metal nanoparticles on the efficiency enhancement of optical emission. Using the example of Au nanosphere embedded in the GaN dielectric, we show that for an emitter with certain original radiative efficiency, placing the emitter too close to the metal sphere does not always produce additional enhancement. Thus our model provides analytical treatment of the luminescence quenching and can be used to optimize both nanoparticle size and its separation from the emitter to yield maximum enhancement.


Impact Of Disorder On Surface Plasmons In Two-Dimensional Arrays Of Metal Nanoparticles, Jacob B. Khurgin, Greg Sun Jun 2009

Impact Of Disorder On Surface Plasmons In Two-Dimensional Arrays Of Metal Nanoparticles, Jacob B. Khurgin, Greg Sun

Physics Faculty Publications

We study the impact of disorder on the properties of surface plasmons (SP) in metal nanoparticle arrays and develop analytical expressions enabling us to ascertain the degree of localization and mixing between the SP states. We show that it might be advantageous to intentionally introduce a certain degree of disorder in order to engineer the improved sensors and detectors.


Practical Enhancement Of Photoluminescence By Metal Nanoparticles, Greg Sun, Jacob B. Khurgin, R. A. Soref Mar 2009

Practical Enhancement Of Photoluminescence By Metal Nanoparticles, Greg Sun, Jacob B. Khurgin, R. A. Soref

Physics Faculty Publications

We develop a simple yet rigorous theory of the photoluminescence (PL) enhancement in the vicinity of metal nanoparticles. The enhancement takes place during both optical excitation and emission. The strong dependence on the nanoparticle size enables optimization for maximum PL efficiency. Using the example of InGaN quantum dots (QDs) positioned near Ag nanospheres embedded in GaN, we show that strong enhancement can be obtained only for those QDs, atoms, or molecules that are originally inefficient in absorbing as well as in emitting optical energy. We then discuss practical implications for sensor technology.


Practical Limits Of Absorption Enhancement Near Metal Nanoparticles, Jacob B. Khurgin, Greg Sun, R. A. Soref Feb 2009

Practical Limits Of Absorption Enhancement Near Metal Nanoparticles, Jacob B. Khurgin, Greg Sun, R. A. Soref

Physics Faculty Publications

We consider the enhanced absorption of optical radiation by molecules placed in the vicinity of spherical metal nanoparticles in the realistic situation that includes perturbation of the optical field by the absorbing molecules. We show that there is an optimal nanosphere radius that gives the strongest enhancement for each combination of the number of absorbing molecules, their absorption strength, and their distance from the nanosphere surface and that the enhancement is strong only for relatively weak and diluted absorbers.